I don't think we know if ME is one disease. CFS is obviously a hodge podge definition, including whatever diseases lie behind ME.
The issue for research is to focus on specific highly defined subgroups. Those with clear neurological symptoms and are fully dependent on support, for example. Such patients should produce better results.
Otherwise this is about criteria. A well funded and designed study could use ANY criteria, because you exhaustively subgroup as part of the study. We now have evidence that even if ME is one disease it still needs subgrouping.
The real issue is cheap and badly applied definitions, with inadequate studies. Some of this is about money. Some of this goes to bias or vested interests. Much of it goes to prejudice when trying to apply for grant money.
A properly conducted Fukuda study, with full testing and subgrouping, would be much much more difficult and expensive than a similar one on bedbound ME patients. Yet it could be done.
It isn't done though. The one that comes closest is the multi-site study, and even that has its limitations.
We need to focus less on names, and more on strict study definitions and patient cohorts. The cheapest way forward is, in my opinion, the most expensive on a per patient basis, but will give better results. That would be a study into CCC or ICC ME patients who are fully bedbound and dependent on support to survive. However there are ethical issues here, they are so very sick, and logistical ones. Any testing would have to come to them, aside from possibly things like MRI in which case the patient might be sedated and transported, at even more cost.
Chronic fatigue patients who are not particularly dysfunctional are low hanging fruit. Its the streetlight effect. They are looking in the easy place rather than looking in the place that will yield the best results. Heck, they might even find eight sets of keys, none of which are the right ones. (The streetlight is sometimes explained by an anecdote where someone was looking for their dropped car keys under a lamp post, rather than where they dropped them, because it was easier there.)
I wonder if Julia Newton's in vitro muscle testing could be developed into a test? That would be a muscle biopsy, but many of us could probably handle that better than a 2 day CPET. I have previously commented though that repeat metabolic testing should provide similar results to the 2 day CPET, and its something I would like to see examined.
The finding that the ICC is much more restrictive is a good thing if confounding diagnoses are properly excluded. It makes for a better research definition.
As far as clinical definitions go, SEID is likely to be more widely utilized to better effect than most. However it also has huge potential for misdiagnosis because most doctors are unlikely to properly apply the definition. Yet that probably occurs even in ICC. Most doctors will not read the supporting material, and so may ignore the issue that exertion intolerance is defined differently to exercise intolerance. They already seem widely ill informed - there are three tests that go back to the 1940s that show severe dysfunction, yet I am betting most doctors cannot name them. Further there might be another test on the way, from 1852. That still requires more validation though.
Jason might use the definitions accurately, but I am betting most doctors will not. So its hard to infer much about clinical practice. Its research usage that is more important. I think we need to pay attention to what he is saying with research in mind.
